Embodiments according to the invention relate to a system, a method and a computer program for detecting an electrostatic discharge event with respect to a device to be monitored.
Some embodiments according to the invention relate to an electrostatic discharge (ESD) monitor solution.
Electrostatic discharge is a serious reason for defects of modern electronic components. For example, modern integrated circuits comprising field effect transistors are often very sensitive to electrostatic discharge events, as the gate oxide thereof can easily be destroyed by excessive electrical field strength. Thus, the production, testing and handling of modern electronic components for semiconductor devices is an example out of many technical fields in which it is desirable to detect electrostatic discharge events.
In the following, some conventional concepts for detecting an electrostatic discharge will be discussed. In the technical literature, the following physical phenomena are listed to capture an electrostatic discharge (ESD) event: light/spark from electric arc of discharge; sound/crackling of discharge; current fields and transient fields; discharge current; and static field.
In the following, some disadvantages of detecting an ESD event on a semiconductor test system (for example a Verigy V93000 semiconductor test system) on the basis of the above-mentioned physical phenomena will be discussed. For further details, reference should be taken to the publication “One of the methods of observing ESD around electronic equipment” of Toshimitsu Takai et al. (Journal of Electrostatics 42 (1998) page 305-320) and to the book “Elektrostatische Entladungen (ESD) and ihre Störwirkung auf elektronische Systeme” of Stephan Frei (Shaker Verlag, ISBN 3-8265-6196-1).
Regarding the light/spark from an electric arc of discharge, it should be noted that this physical phenomenon could be caused by other sources. In other words, said phenomenon is not unique to electrostatic discharge events.
Regarding the sound/crackling of discharge, it should be noted that said phenomenon could be caused by other sources. In other words, said phenomenon is not unique to electrostatic discharge events.
Regarding current fields and transient fields, it should be noted that according to the publication of Stephan Frei: “There are only a few other sources of transient currents and fields and of large static fields. If only currents and fields exceeding certain limits are considered, only electrostatic discharge comes into question as a source in most cases”. However, exploiting the physical phenomenon of current fields and transient fields, there is no discrimination of ESD and non-ESD events. Also, antennas need to be installed to detect current field and/or transient field. With the complex geometry of a semiconductor device-under-test (DUT) interface, electromagnetic waves are reflected, absorbed and shielded. Also, antennas can interact with a semiconductor test system and cause undesired effects. Antennas and sensors installed into a system occupy space and cause “packaging” issues.
With respect to the physical phenomenon of discharge current, the above-mentioned publication of Stephan Frei indicates: “As the current is the most critical effect of an ESD, it is desirable to know the exact temporal devolution of the discharge current for each discharge for the considered environment”.
However, possible conventional solutions for detecting an ESD event on the basis of a discharge current would necessitate a huge effort. For example, all potential discharge locations (i.e. discharge paths) would need to be equipped with current sensors with sufficient bandwidth to detect potential ESD events. Monitoring a large area would necessitate the installation of numerous “current sensors” and would bring along a huge effort. In some cases, monitoring a large area would be impossible due to the high effort. An installation of numerous “current sensors” would cause an intervention into an environment. In some cases, this would mean a significant intervention into an environment. In some cases, the measurement could no longer reflect the reality and would therefore not be meaningful.
However, monitoring a discharge current provides important information on the electrostatic discharge event.
Regarding a detection of ESD events on the basis of a static field, it should be noted that a measurement of a static field is technically easy to implement and provides information on a charge generation. A rapid reduction of the static field strength measured can be interpreted as a discharge. A measurement of a static field can provide information on a frequency of ESD event occurrence. However, it is important to know that large static fields do not necessarily have to lead to an ESD event. Thus, the phenomenon “static field” is not unique to ESD events. Also, a measurement of a static field does not provide information on an intensity of discharge (confer Stephan Frei: “Elektrostatische Entladungen (ESD) and ihre Störwirkung auf elektronische Systeme”, Shaker Verlag, Aachen, 1999, Page 28).
In view of the above discussion, there is a need for a concept for detecting an electrostatic discharge event which can be implemented in an efficient way.